Molecular Mechanisms of Feline Cancers

Feline cancers have not been studied as extensively as canine cancers, though they may offer similar advantages, with cats being immunocompetent animals subject to similar conditions as their human counterparts. The most common feline cancers include lymphoma, squamous cell carcinoma, sarcoma, and mammary tumors, though mast cell tumors were also investigated in this review. As the pathogenesis of many feline cancers remains unclear, this study seeks to elucidate some molecular mechanisms behind feline cancers. Feline lymphoma has been commonly associated with feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV), though in recent years it has appeared more as lymphoma of the gastrointestinal tract. Chromosomal alterations (translocations) due to the virus-associated lymphoma, as well as aberrant gene expression (such as in COX-2 and MDR1) have been identified in the past. While feline lymphoma may be divided into many subtypes, feline sarcoma may be divided into two broad classifications of feline injection site associated (FISS) sarcoma and spontaneous sarcoma, with FISS being a potential model for inflammation leading to tumorigenesis in humans. Previous studies have found multiple chromosomal alterations (including aneuploidy and chromosomal translocations), as well as aberrations in gene expression in feline sarcoma. In the past, oral squamous cell carcinoma has been proposed as a model for human head and neck cancer, and mammary tumors have been proposed as a model for human breast cancers due to similar prognosis and phenotype, as well as higher rate of occurrence in cats than in humans. Mutations have been identified in genes such as TP53, ERBB2, and TWIST1 in feline mammary tumors. c-KIT mutations were commonly located in feline mast cell tumors, though these findings were not particularly significant in terms of correlation to other prognostic indicators. This review seeks to elucidate pathways and treatments for feline cancers for the field of comparative genomics and oncology.